‘The Crusade’ might strike some readers as an unusual choice for inclusion in my top ten of classic Doctor Who adventures as it’s a partially ‘lost’ serial: only two of the four episodes survive (Episode 1 – ‘The Lion’ and Episode 3 – ‘The Wheel of Fortune’). However, the scripts and audio soundtracks survive, and on the evidence of the two extant episodes we can make a reasonable assessment of what the missing episodes would have looked like.